Terrestrial wireless communications systems and methods such as terrestrial cellular communications systems and methods are widely used to provide voice and/or data communications to subscribers within a prescribed geographic area. For example, analog terrestrial cellular communications systems and methods, such as those designated AMPS, ETACS, NMT-450 and NMT-900 have been deployed successfully throughout the world. Digital cellular radiotelephone systems and methods, such as those designated IS-1 36 in North America and GSM in Europe also are being widely used. Moreover, Personal Communication Services (PCS) cellular systems and methods, such as those designated IS-95, PCS-1900 and PACS in North America, DCS-1800 and DECT in Europe, and PHS in Japan, also have been deployed for voice and/or high bit-rate data communications.
As is well known to those having skill in the art, terrestrial cellular communications systems and methods may employ a plurality of terrestrial components, also referred to as base stations, which transmit communications to a plurality of wireless terminals over a terrestrial cellular frequency band and receive communications from the wireless terminals over the terrestrial cellular frequency band. The wireless links that are used to transmit communications from the base stations to the wireless terminals are also referred to as forward links, and the wireless links that are used to receive communications from the wireless terminals at the base stations are also referred to as return links.
The following Table illustrates frequency bands that have been designated for terrestrial cellular and satellite cellular use in the United States. These frequency bands are only representative, and other frequency bands may be used within or outside the United States.
TABLEForward LinkReturn LinkTerrestrial Cellular869.01–893.97MHz824.01–848.97MHzTerrestrial Cellular1930–1990MHz1850–1910MHzPCSSatellite Cellular1525–1559MHz1626.5–1660.5MHzL-BandSatellite Cellular2484.39–2499.15MHz1610.73–1625.49MHzBig LEO-BandSatellite Cellular2165–2200MHz1990–2025MHzS-Band
The overall design and operation of terrestrial cellular communications systems and methods are well known to those having skill in the art, and need not be described further herein. Moreover, as used herein, the term “wireless terminal” includes cellular and/or satellite radiotelephones with or without a multi-line display; Personal Communications System (PCS) terminals that may combine a radiotelephone with data processing, facsimile and/or data communications capabilities; Personal Digital Assistants (PDA) that can include a radio frequency transceiver and a pager, Internet/intranet access, Web browser, organizer, calendar and/or a global positioning system (GPS) receiver; and/or conventional laptop and/or palmtop computers or other appliances, which include a radio frequency transceiver.
As the number of users and/or applications in a terrestrial wireless communications system or method continue to increase, it may be desirable to increase the capacity and/or quality of service of the forward and/or return links that are used for communications between the base stations and the wireless terminals. One way to increase this capacity and/or quality of service is to increase the frequency spectrum that is available for use by the terrestrial wireless communications systems and methods. However, as is well known, the radio frequency spectrum generally is tightly controlled by governmental agencies, such as the Federal Communications Commission (FCC) in the United States. The FCC regulates the frequency bands that electronic equipment may use to transmit information, and also regulates the maximum in-band and/or out-of-band power levels that may be radiated by the specific equipment type.